1. Technical Field
The present invention relates to a switch circuit, a filter circuit, and a test apparatus. In particular, the present invention relates to a switch circuit for switching whether to output an input signal, and to a filter circuit and a test apparatus including the switch circuit.
2. Related Art
A T switch circuit and an L switch circuit, which use a semiconductor switch, are known to be fast and have a favorable insulation property when opened. The T switch circuit and the L switch circuit include a first semiconductor switch for switching short-circuit/opening of an input end and an output end, and a second semiconductor switch for switching short-circuit/opening of a transmission path and a ground potential, where the transmission path is of the input end and the output end.
In the T switch circuit and the L switch circuit, the second semiconductor switch is opened when the first semiconductor switch is short-circuited, and is short-circuited when the first semiconductor switch is opened. Consequently, when the first semiconductor switch is opened, the second semiconductor switch can ground, to a ground potential, a high-frequency signal inputted via a parasitic capacitance of the first semiconductor switch. Accordingly, the T switch circuit and the L switch circuit do not output a leakage signal inputted from either the input end or the output end from the other end, thereby leading to improvement in insulation property at the time of opening.
So far, no related patent document is recognized, and so the description thereof is omitted.
A semiconductor switch has a capacitance between output terminals. Therefore, while the first semiconductor switch is short-circuited, a T switch or an L switch has deformed a signal passing between the input end and the output end due to the capacitance between output terminals that depends on the voltage between terminals in the second semiconductor switch.